The one and single most obvious thing for me from the whole talk was "it's about the people". Watching it one will notice the amount of people that started contributing in there free time and how fast LibreOffice grows in number of contributors. As one that works almost entirely with Eclipse.org projects (especially Eclipse as an IDE) this made me ask a very basic question:

How did a pure end-user application managed to attract more developers to spend improving it in their free time than an IDE ?

I started to think about initial experience I had trying to improve various plugins and realized that we do fail entirely in welcoming new committers. Even after one has number of patches in, if one just opens a bug(gerrit review) and attaches his/her patch - nothing happens for months (even years!). Or the patch will comments why it can't happen now and nothing will happen for months/years again. Now I'll try to fight some of the most common myths used to explain the situation:

there is release pressing - this is seen for milestones, SR releases, etc. But there is always something pending and most of the time people start with so small contributions that they can hardly affect the whole release train. Potential contributors might be more happy if instead of saying it can't happen now and forget it, we do comment a week later once the M-build is out (this covers most of the calendar year) and work with the contributor to get his change in.

it gains us nothing - wrong! for at least two reasons: First: one of your users identified the need for it and cared to spend time to contribute it back, one could bet that he/she see it as important; Second: even if there will be no technical benefit immediately - that's one more contributor and this makes difference soon after that.

old versions depend on something that this patch changes - You know there is a reason for calling a version an old one. Don't hold the new development - we have the awesomeness of git - branching, cherry-picking and so on can hardly be easier. Old way of doing something belongs to maintenance branches. Here we come to catch 22 - there are not enough people to support two ways but we don't want new contributors too. New people need new things.

this part of the code is "tabu" - only blessed ones can touch it. Telling a potential contributor - "you're not smart enough" isn't it ? Well, I read it differently - if in my code there is something so sensible that I should be afraid is someone touches - it needs a fix (or ever rewrite?) as soon as possible so it can continue improving as normal part of the codebase. As long as someone starts spending his time on it of course.

it's not tested with other version of third party library - this is seen really often from my point so it's like a personal rant. If someone requests a dependency range to be bigger one can think that he tried it or that even a product using the version outside of the range is shipped. And this means nothing as the project can continue ship its preferred version but you can make the life of people depending on your code easier for no cost.

the contributor already ships a fork so he/she can continue do that - If one ships a fork and submits patches back it clearly means he doesn't want to do that but he is forced to do that because the project is not interested to grow in the area he needs.

If we want to grow as community members, everyone has to go through his projects bugzilla/gerrit see for pending patches or requests and make the easiest one come in the next release. Or we will soon get to the point where people will not even report bugs as they would not believe anyone will look at the bug opened and that would be a failure growing to disaster. Seeing even well respected people withing the community having to poke numbers of time for really simple patches to be applied makes me very sad as this is pure energy lost. One can fix few more bugs instead of rebasing patch 3 times and poking 5 times.

It's not too late for a change we need to just encourage people by accepting their changes or work with them till the change is in a good enough change. Just a bit more openness and trust to new contributors is needed. So do we actually want to grow the community?